Plates and perches sold by the pair
 
These pieces are helpful for swapping in a sterling 10.5 or similar rear axle in your 1979 and older truck. They are designed for 3.625" diameter axle tubes and 3" wide leaf springs.

Trucks that are 34" in the back require removing the oem Sterling perches and welding new perches closer in. Trucks that are 37.5" in the rear do not require any modification to the  existing axle perches.
 
For the plates that sit on top of the leaf, there is no reason you can't reuse the oem Super Duty plates. But most of the time they are rusty or maybe your axle didn't come with them. These plates I make are heavy 3/8" thick steel and accept up to 5/8 U bolts. They also look good for what its worth! These work great with Skyjacker FR173S springs
 
A couple other notes about the sterling swap, even if not relevent to these parts:
-often you need to make a different shock mount bracket on the axle
-The sterling axles seem to mostly all have a flange rather than a yoke for the driveshaft. The Yoke size was 5.750 on the swaps I have done and Dana Spicer part number 3-2-1859 is helpful if you will be using 1350 joints
-The parking brake cables of the sterling axle can be connected to the forward 70's Ford parking brake cable. One points rearward off of the axle so it needs to wrap around. Be careful it doesnt rub against the tire